The free-viewpoint video technology is a technology for playing back video composed of images shot by the user at arbitrary viewpoint positions.
In the free-viewpoint video technology, among videos shot at different viewpoints by a plurality of cameras (hereinafter a video which is shot at one viewpoint is referred to as a “viewpoint video”), a viewpoint video that is closest to a viewpoint position selected by the viewer is played back, or a video of the viewpoint position of the viewer, which is generated by interpolation by using a viewpoint video that is closest to the viewpoint position of the viewer, is played back (Patent Literature 1).
In such free-viewpoint video technology, to accurately play back videos which are shot at various viewpoint positions, as many viewpoint videos as possible are required.